I'm trying to use the Motion > Content > Ethereal background to create a looping background for an animation. Is there a way to set it to loop automatically? Tried applying the loop behavior but it won't "stick" and there's no selection in the properties tab > timing pane for looping? I'm kinda stuck using the Ethereal background because it's already been used elsewhere in the project.

Thanks.

You may have to Group the clip if it is dynamically rendered then just open the "timing" panel in the inspector for the group and change the "End Condition" to "Loop."